Field of the Invention
The present invention relates to a piezoelectric actuator and a liquid discharging apparatus provided with the piezoelectric actuator.
Background Art
There is known an ink-jet head as a liquid discharging apparatus. The ink-jet head is provided with a head body formed with a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles, respectively; and an actuator including a plurality of piezoelectric elements corresponding to the plurality of pressure chambers, respectively.
The plurality of pressure chambers in the head body are arranged corresponding to the plurality of nozzles, respectively, and construct four pressure chamber rows arranged side by side in a direction orthogonal to a nozzle aligning direction in which the nozzles are aligned. The actuator has a vibration plate covering the plurality of pressure chambers, a piezoelectric layer arranged on the vibration plate, and a plurality of individual electrodes which are arranged at an upper side of the piezoelectric layer while corresponding to the plurality of pressure chambers, respectively. A portion, of the piezoelectric layer, which corresponds to each of the pressure chambers is one piezoelectric element among the plurality of piezoelectric elements. Namely, the ink-jet head has a construction in which the plurality of piezoelectric elements are aligned in four rows in accordance with the alignment of the plurality of pressure chambers. Further, the vibration plate is formed of Cr (chromium) or a Cr-based alloy and faces the plurality of individual electrodes, with the piezoelectric layer being interposed between the vibration plate and the individual electrodes. The vibration plate also serves as a common electrode for the plurality of piezoelectric elements.
A plurality of electrical contact portions are arranged on the upper surface of the piezoelectric layer, at one end portion in the direction orthogonal to the arranging direction of the nozzles. From the plurality of individual electrodes constructing the piezoelectric elements aligned in four rows, a plurality of drive wires are extended toward the electric contact portions, respectively. Note that drive wires included in the plurality of drive wires and corresponding to piezoelectric elements, which are included in the plurality of piezoelectric elements and which constructs a piezoelectric element row included in the four piezoelectric element rows and located on a side opposite to the electric contact portions, are drawn through spaces between piezoelectric elements constructing another piezoelectric element row which is located closer to the electrical contact portions. An IC chip for applying voltage to each of the piezoelectric elements is connected to the electrical contact portions.